A force acts on a block as shown in figure. Find time when block loses contact with surface.

The limiting value of static friction between two contact surfaces is ........... 

A wooden block of mass $M$ resting on a rough horizontal surface is pulled with a force $F$ at an angle $\phi $ with the horizontal. If $\mu $ is the coefficient of kinetic friction between the block and the surface, then acceleration of the block is

In figure, the coefficient of friction between the floor and the block $B$ is $0.2$ and  between blocks $A$ and $B$ is $0.3$. ........ $N$  is the maximum horizontal force $F$ can be  applied to the block $B$ so that both blocks move together .

A uniform rope of length l lies on a table. If the coefficient of friction is $\mu $, then the maximum length ${l_1}$ of the part of this rope which can overhang from the edge of the table without sliding down is

The coefficient of static friction, $\mu _s$ between block $A$ of mass $2\,kg$ and the table as shown in the figure is $0.2$. What would be the maximum mass value of block $B$ so that the two blocks $B$ so that the two blocks do not move? The string and the pulley are assumed to be smooth and masseless ....... $kg$ $(g = 10\,m/s^2)$